Where Is a NEMA Type 4X Used?


A NEMA 4X enclosure is designed to resist penetration by water sprays and be dust-proof and corrosion-resistant. It is the ideal electrical enclosure for applications that are subject to corrosion, wash down and heavy weathering. Enclosure cooling systems fitted to such enclosures should have the same NEMA type rating.

NEMA 4X Requirements

NEMA 4X is sometimes referred to as waterproof but this is not strictly correct because a NEMA 4X enclosure cannot be submerged in water; however, the enclosure must be resistant to an intense water spray without allowing any water ingress.

NEMA 4X enclosures must also pass a rigorous series of corrosion tests. These include 1200 hours of exposure to moist air containing carbon dioxide and sulfur dioxide and 800 hours of salt spray tests. Additionally, all enclosures must be dustproof and resistant to damage caused by the formation of ice. Although not mandatory, such enclosures are generally manufactured from stainless steel as this provides the ideal substrate to resist the corrosion and weathering tests required to achieve the NEMA rating.

Applications for NEMA 4X Enclosures

The range of applications for NEMA 4X enclosures is wide, extending from those where the enclosure must withstand extremely aggressive conditions to the ability to retain cosmetic appearance and functionality under all conditions. The resistance to corrosion, water sprays and adverse weathering represent three important applications for NEMA 4X enclosures.

Presence of Corrosive Substances

In facilities where corrosive gases and vapors are present, NEMA 4X enclosures protect electrical equipment from contamination and harm. Examples of such industries include waste water plants and plants handling corrosive chemicals. It’s important to note that as the corrosion tests only include certain conditions, the resistance of seals and the enclosure materials of construction to particularly aggressive chemicals should be verified before use. A NEMA 4X enclosure is also not suitable for use in hazardous areas where explosive vapors may exist; however, enclosure cooling systems approved for certain categories of hazardous areas are available.

Equipment Subject to Wash Down and Heavy Splashing

A NEMA 4X enclosure is suitable for use in food processing plants when equipment is washed down with either water or chemical solutions to maintain hygiene standards. It’s also suitable for other facilities that use water sprays such as dairies or vehicle cleaning services, and where high pressure cleaning equipment is utilized.

In some facilities, there’s a risk of accidental splashing and contamination of equipment from fluids used during processing. A good example of this is the pulp preparation areas of paper mills. NEMA 4X enclosures are well suited for these environments and additionally are suitable for use in marine environments where equipment may be exposed to salt water. In marine environments, 316 stainless steel should be specified.

All-Weather Outdoor Locations

Although NEMA 4 enclosures are designed to be weatherproof and suitable for outdoor use, there may be applications when NEMA 4X enclosures are more suitable. These include extremely dusty locations that are subject to wind abrasion. Other examples are hot, humid locations such as found in Florida and in coastal environments where the corrosion rates of mild steel equipment are high. NEMA 4X stainless steel enclosures are more durable and retain their cosmetic appearance in locations where painted steel enclosures may suffer accelerated wear or corrosion.

Choose NEMA 4X for Durability

Thermal Edge NEMA type 4X enclosure cooling systems fabricated from high quality stainless steel maintain the NEMA 4X rating of electrical enclosures and protect electrical equipment. Besides complying with NEMA 4X requirements, numerous options are available to manage enclosures’ internal environments so as to ensure electrical equipment remains cool, dry, and dust free. All air conditioners are UL approved. Contact our sales team for additional information.